The present disclosure relates generally to LED backlight assemblies.
Light emitting diodes (LEDs) are used as light sources for a variety of applications. Some LED light source applications include commercial graphic displays and other lighted displays. An LED emission pattern can vary from a narrow, forward directed beam to a wide cone. Side emitting LEDs are also used in some applications.
In these applications, the LEDs are normally placed on the back or the side of a backlight. When LEDs are placed on the back of the backlight, bright spots caused by the LED sources can be visible in the backlight output, thereby causing a non-uniformly lit sign box or display.
In these applications, placing diffusers in the backlight can minimize the bright spots. These diffusers can reflect the light around the backlight to homogenize the emitted light, but every reflection can cause a loss of light, and the diffuser can also reduce transmitted light.
Another way to reduce the perceived LED bright spots in a signbox or display is to make the signbox or display deeper. However, this also causes a loss of brightness due to increasing distance from the light source to the display or sign face (light emission surface). It can also result in significant cost increases due to the need for additional materials.